【正文】 師在 研發(fā)設(shè)計(jì) 殼 體結(jié)構(gòu)的過(guò)程中往往會(huì)受到 一系列約束 條件 的 限制 。 建筑美學(xué) 利用 可 用幾何數(shù)字建模工具 ， 更多的建筑師 通過(guò)把他們的工作建立在審美(通常是主觀的 )條件上來(lái)實(shí)現(xiàn)結(jié)構(gòu)的布景效果。這些自由延伸的構(gòu)造會(huì)在建筑物產(chǎn)生不利的內(nèi)力，也會(huì)在建筑物的表面造成無(wú)法預(yù)料的其它不利力的影響。一個(gè)合理 化 的設(shè)計(jì)， 在初步設(shè)計(jì)階段 ，需要超越傳統(tǒng)布局經(jīng)驗(yàn) 而且要以結(jié)構(gòu)的完整性設(shè)計(jì)為中心 (Leach et al . 2021)。 幾何造型 幾何 學(xué) 是一 種 工具 , 古代建筑模型的構(gòu)造就 已經(jīng)使用。 花之圣母大教堂 的圓頂， 意大利 (建于 1436 年 ),由菲利普 施萊希和漢斯 通過(guò)結(jié)構(gòu)形式考慮 結(jié)構(gòu)效率 幾乎所有 傳統(tǒng)的結(jié)構(gòu)設(shè)計(jì) 原理 (從材料選 取 、 剖面圖 ,節(jié)點(diǎn)類型 , 整體微分幾何 、和支 撐 條件 ), 整體微分幾何 學(xué) 都是 確 定一個(gè) 殼體結(jié)構(gòu) 是否是穩(wěn)定的 ,安全的 ,足夠的 支撐 。 彎曲 的殼 體 需要通過(guò)尋找 “ 正確 ” 的幾何形狀 來(lái) 避免 因自重 而 只有膜 起 作用 的 結(jié)果。 為 鋼殼 結(jié)構(gòu) 找到一個(gè) 纜索系統(tǒng) 的重要性 首先在于 這樣一個(gè) 事實(shí) ， 自重 (鋼和玻璃引起的 重力負(fù)載 ) 主要貢獻(xiàn)的負(fù)載被抵 消 。這主要因?yàn)楹茈y找到最優(yōu)形式對(duì)于那些依靠拉伸和壓縮膜 應(yīng) 力 相互抵消的殼體結(jié)構(gòu) 。 在 NSA 庭院競(jìng)爭(zhēng)設(shè)計(jì)鋼玻璃殼 體結(jié)構(gòu) 在不久的將來(lái) ， 荷蘭海事博物館計(jì)劃徹底 的 改造 項(xiàng)目 。 2021 年 ,奈伊和 其 合作伙伴 ,一個(gè)總部位于布魯塞爾的工程設(shè)計(jì)咨詢公司 , 鋼和玻璃 結(jié)構(gòu) 外殼設(shè)計(jì) 贏得 了 這次比賽。 Laurent Ney2。 Steel。 Netherlands. Author keywords: Shape。 Historic courtyard。 see Fig. 1。 (b) prefabricated Crystal Palace (United Kingdom, built in 1851) was dismantled soon after its intended use (reprinted from originally from Tallis’ History and Criticism of the Crystal Palace. 1852)。ades) are restrained in the vertical direction but allowed to move in the direction perpendicular to the fa231。 and _vt ix 5acceleration at node i in direction x at time t. Expressing the acceleration term in Eq. (1) in finite difference form and rearranging the equation gives the recurrence equation for updating the velocity ponents vt1Dt=2 ix Dt Mi Rt ix t vt2Dt=2 ix e2T Hence, the updated geometry projected to time t1Dt=2 xt1Dt i xti t Dtvt1Dt=2 ix e3T Eqs. (2) and (3) apply for all unconstrained nodes of the grid in each coordinate direction. These equations are nodally decoupled, in the sense that the updated velocity ponents are dependent only on previous velocity and residual force ponents at a node. They are not directly influenced by the current t1Dt=2 updates at other nodes. Having obtained the plete updated geometry, the new link forces can be determined and resolved together with the applied gravity load ponents Pix to give the updated residuals Rt1Dt ix Pix t P _ F L _t1Dt m _ xj 2xi _t1Dt e4T for all elementsm connecting to i, where Ft1Dt m 5force in member m connecting node i to an adjacent node j at time。zi 2f exi。 ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 eL2xT2 t 1 eL2yT2 s t ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 eL2xT2 t 1 eL t yT2 s t ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffif。 yT e8T For the NSA roof, f ex。ades, the largest vertical reactions are found at the courtyard corners. This clearly shows that the boundary zones of the shell itself acts as truss along the boundary walls. After the numerical formfinding process, the resulting, generated geometry of the shell is subjected to a nonlinear analysis. The real values of elastic and bending stiffness need to be used during the structural analysis of the grid shell, the results of which are verified against the Building Codes (European Committee for Standardization 1990, 1991, 1993). In the structural analysis, the shell is subjected to the loading binations of selfweight (glass kN/m2, aluminum profile kN/m, and steel profile in function of crosssectional area steel density kN/m3), live load ( kN/m2), maintenance load (1 kN/m2), impact load ( kN over Fig. 5. The shape of the shell is formfound to achieve membrane action 210 / an area of 10 3 10 cm), thermal load (), snow load (varying between and kN/m2), and wind load (varying between and kN/m2). Because the cupola should express a clarity of form resembling a fine line drawing against the sky, all 3368 elements are dimensioned as steel sections with widths of 40 or 60 mm and with variable height (100–180 mm). The total weight of the steel roof is 100,000 kg, and the ring beamweighs 40,000 kg. The largest ultimate limit state axial forces occur in the grid diagonals (pressive force 940 kN) and edge beam (tensile force 2,600 kN). A static analysis shows that all elements are loaded far below their critical buckling load by a factor of 2. The maximum shell deflection is 170 mm. The deflection values under wind loadings are relatively small because of the suction effect. A dynamic analysis finds an eigenfrequency value of . The different analyses show that the shell satisfies all structural criteria. The glass cladding has two layers: one bottom layer with two panes of 6mm half toughened glass and one top layer of 8mm toughened glass. The issue of facet planarity needed for glass panes imposes a slight modification of the form found geometry of the shell. For this project, a specific method based on origami folding was derived and will be discussed next. Sometimes, planarity of mesh might not be desired (., Foster and Partners’ design for the Smithsonian Institute). Because of steel digital fabrication techniques [pioneered in the design of the roof over the great courtyard of the British Museum (Barnes and Dickson 2021)], standardization of meshes and, thus, elements and nodes, is no longer considered crucial, but mesh planarity of nontriangular meshes is still a vital issue. Construction Constraints Adapt the Irregular Faceted Catenary Surface In this project, the plan geometry of the roof is based upon Fig. 6, in which 16 equally spaced points around a circle are all joined by a total of 120 straight lines. The square plan of the roof itself (Fig. 6) is the central square part of the circle with only the four corner points remaining from the original 16. Thus, one can calculate exi。 this load value differs for most nodes be